A researcher grew two identical young shoots for 8 hours.
Shoot A received light equally from all directions. Shoot B received light from one side only.
The researcher measured the auxin concentration and the increase in length on each side of the shoots.
| Shoot and side | Auxin concentration in tissue in ng per g | Increase in length in mm |
|---|---|---|
| Shoot A, side 1 | 20 | 2.2 |
| Shoot A, side 2 | 21 | 2.3 |
| Shoot B, side facing the light | 12 | 1.4 |
| Shoot B, shaded side | 34 | 4.0 |
Use the data to explain why shoot B bent towards the light but shoot A remained straight.
After 8 hours, the researcher changed the conditions so that light reached shoot B equally from all directions.
Suggest how shoot B would grow after this change. Explain your answer.
87 exam-style questions on AQA GCSE Biology 5.4 Plant hormones, covering 5.4.1 Control and coordination and 5.4.2 Use of plant hormones (HT only). Each one has a worked solution and a mark scheme showing where the marks go.